Power transformer
- The function of transformer is mainly used to change AC voltage.
- Main parameters of transformer are incoming voltage, outgoing voltage and frequency.
- Transformer capacity unit is KVA.
- Indoor or outdoor.
How to choose power transformer?
Transformers include oil-immersed transformers and dry-type transformers. The same is that all power transformers have iron cores for magnetic circuits and windings for circuits. The biggest difference is between “oil type” and “dry type”, that is, the cooling medium of the two is different. The former uses transformer oil (of course, there are other oils such as β oil) as cooling and insulation medium, and the latter uses air or other gases such as SF6 as cooling medium.
Oil-immersed transformer is to place the body composed of iron core and winding in an oil tank filled with transformer oil. Dry-type transformers often encapsulate the iron core and winding with epoxy resin casting. There is also a kind of non encapsulated transformer which is widely used now. The winding is impregnated with special insulating paper and special insulating paint to prevent the winding or iron core from being damp. And because of the different classification methods of technology, use and structure, they derive different categories, so we say it from a narrow point of view.
Output and consumption of oil-immersed transformers and dry-type transformers
At present, the voltage level of dry-type transformer is only 35KV, and the capacity is smaller than that of oil-immersed transformer, about 2500KVA. In addition, the manufacturing process of dry-type transformer is more complex and costly than that of oil-immersed transformer with the same voltage level and capacity. Therefore, there are still many oil-immersed transformers in terms of consumption.
Due to its environmental protection, flame retardant, impact resistance and other advantages, dry-type transformers are often used in indoor power supply and distribution stations with high requirements, such as hotels, office buildings, high-rise buildings and so on.
Advantages and disadvantages of oil-immersed transformers and dry-type transformers
Oil-immersed transformer has the advantages of low cost and convenient maintenance, but it is combustible and explosive. Due to its good fire resistance, dry-type transformer can be installed in the load center area to reduce voltage loss and power loss. However, dry-type transformer has high price, large volume, poor moisture and dust resistance, and high noise.
- The price of dry-type transformer is more expensive than oil immersed transformer.
- In terms of capacity, there are more oil immersed transformers with large capacity than dry transformers.
- Dry-type transformers are required in complex buildings (basement, floor, roof, etc.) and densely populated places. The oil immersed transformer is used in an independent substation.
- The transformer in the box transformer generally adopts dry-type transformer. Oil immersed transformer is generally used for outdoor temporary power.
- During construction, dry transformer and oil transformer can be selected according to the space. Oil immersed transformer can be selected when the space is large, and dry-type transformer can be selected when the space is crowded.
- The regional climate is humid and muggy, so it is easy to use oil-immersed transformer. If dry-type transformer is used, forced air cooling equipment must be equipped.
Oil-immersed transformers delivery
Oil-immersed transformers ordered by Zambian customer have been shipped successfully.
- Model No.: S11-M-100/11-0.4
- Rated capacity: 100KVA
- Rated voltage: 11/0.4KV
- Phase: 3
- Vector group: D.yn11
- Cooling method: ONAN
- Operating condition: Outdoor
- Impedance voltage: 3.87%
- Insulation class: LI 75, AC 35
| Tapping position | High voltage | Low voltage | ||
|---|---|---|---|---|
| Voltage/V | Current/A | Voltage/V | Current/A | |
| I | 11550 | 5.25 | 400 | 144.3 |
| II | 11275 | |||
| III | 11000 | |||
| IV | 10725 | |||
| V | 10450 | |||
